Lens blocking device

Claim 1

AN IMPROVED BLOCKING DEVICE FOR USE WITH A PLASTIC LENS BLANK WHICH IS SUBSTANTIALLY NO LARGER IN CIRCUMFERENCE THAN THE BLOCKING DEVICE OF THE TYPE HAVING ONE FINISHED SURFACE AND ONE UNFINISHED SURFACE FOR THE PURPOSE OF SUPPORTING THE BLANK WHILE A PERSCRIPTION CURVE IS FORMED ON THE UNFINISHED SURFACE, SAID BLOCKING DEVICE COMPRISING: A BLOCKING BODY FORMED WITH A LENS BLANK SUPPORTING SURFACE WITH A CURVATURE CONFORMING GENERALLY TO THE CURVATURE OF THE FINISHED SURFACE OF THE LENS BLANK TO BE SUPPORTED THEREON SO THAT THE FINISHED SURFACE OF THE LENS BLANK CAN BE BONDED THERETO AND SUPPORTED THEREON BY A THIN LAYER OF BONDING AND SUPPORTING MATERIAL OF UNIFORM THICKNESS, AND LENS BLANK SPACING AND POSITIONING MEANS MOUNTED ON AND PROJECTING FROM THE SUPPORTING SURFACE OF THE BLOCKING BODY ADJACENT PERIPHERAL EDGE PORTIONS THEREOF, SAID SPACING AND POSITIONING MEANS BEING OF UNIFORM HEIGHT SO AS TO BE ENGAGEABLE WITH THE FINISHED SURFACE OF THE LENS BLANK AT LEAST AT THREE POINTS THEREOF TO THEREBY MAINTAIN ALL PORTIONS OF THE FINISHED SURFACE IN SUBSTANTIALLY PARALLEL AND EQUALLY SPACED RELATIONSHIP WITH CORRESPONDING PORTIONS OF THE SUPPORTING SURFACE OF THE BLOCKING BODY.